1. Field of the Invention
The present invention relates to a package type multi-layer thin film capacitor for large capacitance, and more particularly, to a package type multi-layer thin film capacitor for large capacitance that may prevent, using a lead member, impact or heat transferred from an outside from being directly transferred to a ceramic sintered body and thereby prevent cracks from occurring due to the impact or the heat.
2. Description of the Related Art
A multi-layer ceramic capacitor (MLCC) has been widely utilized as an electronic part for miniaturization, high power, and high reliability. The MLCC is formed by alternately disposing dielectric layers and internal electrode layers. The use of the MLCC has been expanded to an industrial field or an electric vehicle field and thus, large capacitance thereof has been required. The large capacitance of the MLCC has been performed by manufacturing a green sheet layer as a thin film and thereby increasing the number layers, or by increasing a vertical length and a horizontal length of the internal electrode layer to be tens of mm and thereby increase a surface area.
Hereinafter, a configuration of the conventional MLCC (hereinafter, also referred to as a thin film capacitor) in which the green sheet layer is manufactured as the thin film will be described with reference FIG. 1.
In FIG. 1, the conventional multi-layer thin film capacitor 1 includes a ceramic sintered body 2, a plurality of green sheets 3, a protecting layer 4, and an external electrode 5.
The ceramic sintered body 2 is formed by multi-layering and sintering the.a plurality of green sheets 3, and each of the plurality of green sheets 3 includes a dielectric thin film sheet 3a and an internal electrode layer 3b. The dielectric thin film sheet 3a is formed as a thin film with a thickness of a few to hundreds of μm by applying a high-dispersed slurry production method and a die-coater or a lip coater. The internal electrode layer 3b is formed by applying a metal material such as copper (Cu) on the surface of the dielectric film sheet 3a. 
When a green sheet member 2 is formed by alternately disposing the plurality of green sheets 3, the protecting layer 4 is formed by wrapping the peripheral surface of the green sheet member 2 excluding one side and another side of the green sheet member 2 using an insulating film. When the protecting layer 4 is formed, the multi-layer thin film capacitor 1 is manufactured by forming an external electrode 5 for electrically connecting an internal electrode layer 2b on one side and another side of the green sheet member 2. The external electrode 5 is employed when mounting the multi-layer thin film capacitor 1 on a soldering pad 7a of a printed circuit board 7.
When applying the multi-layer thin film capacitor 1 to an electric vehicle, large capacitance may be required. The multi-layer thin film capacitor 1 having large capacitance has a significantly wide surface area compared to a thickness. Accordingly, as shown in FIG. 1, a crack 6 may easily occur due to an environment of a vehicle, for example, temperature, impact, and the like.
In the multi-layer thin film capacitor 1, the crack 6 may very easily occur due to physical impact since the external electrode 5 is directly bonded on the soldering pad 7a of the printed circuit board 7, or the ceramic sintered body 2 is formed of different materials such as a dielectric material and a metal material. In addition, when the multi-layer thin film capacitor 1 is exposed to a high temperature environment, the crack 6 may easily occur due to different coefficients of expansion or different coefficients of brittle.
In the conventional multi-layer thin film capacitor, an external electrode mounted on a printed circuit board is directly connected to a ceramic sintered body and thus, impact or heat may be transferred to the ceramic sintered body through the external electrode. Accordingly, in the conventional multi-layer thin capacitor, cracks may easily occur due to such impact or heat.